Laminate Structure with Embedded Cavities for Use with Solar Cells and Related Method of Manufacture

ABSTRACT

An integrated laminate structure ( 702   a,    702   b,    801 ) adapted for application in the context of solar technology, includes a first carrier element ( 704, 804 ), such as a piece of plastic or glass, optionally including optically substantially transparent material enabling light transmission therethrough, a second carrier element ( 702, 802 ) provided with at least one surface relief pattern ( 802   a ) including a number of surface relief forms ( 708 ) and having at least one predetermined optical function relative to incident light, the second carrier element including optically substantially transparent material enabling light transmission therethrough, the first and second carrier elements being laminated together such that the at least one surface relief pattern has been embedded within the established laminate structure and a number of related cavities ( 709 ) have been formed at the interface of the first and second carrier elements. An applicable method of manufacture is presented.

CROSS REFERENCES TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.13/640,104, filed Oct. 9, 2012, which is a U.S. national stageapplication of PCT/FI2011/050299, filed Apr. 6, 2011, which claimspriority to U.S. Provisional Application Nos. 61/282,818 and 61/388,233,filed Apr. 6, 2010 and Sep. 30, 2010, respectively. The contents ofthese applications are incorporated herein by reference.

FIELD OF THE INVENTION

Generally the present invention pertains to optics. In particular,however not exclusively, the present invention concerns laminatestructures with embedded, optically functional cavities andmanufacturing thereof in the context of solar technology.

BACKGROUND

Traditionally microstructures such as microprisms or gratings ofdifferent optics-containing devices such as lighting apparatuses andelectronic apparatuses have been exclusively produced on surface areasof optically transparent substrates. These structures may have beenoriginally configured to (re)direct, couple or otherwise interact withthe incident light in a certain predetermined manner, but positioningthereof on the surface of the material has typically caused a number ofproblems and defects arising, if not immediately, at least in the longterm.

Namely, optically meaningful surface relief structures such as couplingoptics are very often subjected, naturally depending on the usescenario, to stress caused by various external factors such ascontamination due to dust, sand, water, grease and dirt in general. Inaddition, the surface forms are generally vulnerable to impacts byexternal objects, which may break, deform and damage these delicatestructures of potentially just micrometer or nanometer size, forexample. Even the pressure introduced by a purposefully contactedexternal element may damage the surface structure patterned on thecontact surface and hinder the desired function thereof.

To illustrate some of the above issues, FIG. 1a visualizes, particularlyin the exemplary context of solar cells, two initial problems that mayalso occur together in the same use scenario generally incorporatinglight propagation and medium boundaries. On the left, the light emittedby a light source such as the sun and incident 106 on a cover glass 102of a solar cell 104 with a noticeable angle of incidence is undesirablypartially reflected 108 from the surface of the cover glass 102 at theair-glass interface. Secondly, the light fraction passed into the coverglass 102 is still further partially reflected internally 110 from theglass-solar cell interface 103. Provided that the external medium isair, the corresponding refractive indexes may be nair, n1 and n2 for themedium, material of the glass and for the top portion of the cell,respectively. Ultimately, merely a limited amount of incident light suchas the light rays 112 that are substantially perpendicularly incident onthe cover glass 102 may thus pass through the cover glass 102 and enterthe solar cell 104 without considerable amount of relatedelectromagnetic energy lost due to reflections at the interfacesencountered on the overall optical path. Thereby, the range of incidentangles enabling efficient incoupling and total efficiency remainsnarrow.

To cope with the afore-explained interfaces and to improve the couplingefficiency, a solution substantially following the one of FIG. 1b couldbe considered. The outmost layer 102, such as the above cover glassprotecting the underlying solar cell 104 and thus being again the firstelement to receive the incident light, has been provided with a surfacerelief pattern 114 configured to couple and redirect the light towardsthe cell 104 within a predetermined angle. The pattern may have beenspecifically constructed to redirect the light rays 120 moreperpendicularly to the cell 104, for example. However, as the structureis obviously easily contaminated by additional material 118 such as dustparticles or water droplets stuck into the recesses defined by thesurface relief forms, the effect of the pattern 114 sooner or laterturns out inferior as at least part of the incident light is actuallyreflected by the contamination 118 and/or is coupled towards the cell104 in somewhat random angle, which may cause further undesiredreflections at the glass-cell boundary 103 and cause reduced overallefficiency of the provided structure.

Still staying in the exemplary context of solar cells, the achievedoverall efficiency of the contemporary solutions may be surprisinglylow, possibly around 15% or below, greatly due to thecontamination-induced reflections and miscoupling, surface reflections,internal reflections, such as reflections at medium boundaries betweene.g. ITO (indium tin oxide) layer and other layers commonly applied inthe solar cells' optical structures. Major portion of the sunlightincident on the optical structure comprising the solar cell is notutilized because certain incident angles are basically disregarded bythe conventional optics utilized therewith. In other words, in theillustrated context of solar energy one could say that only directsunlight reaching the solar cell vertically adds to the efficiency ofthe solar cell that is thus extremely sensitive to the sun position.

Historically, even the use of laser has been suggested in generatinginternal, localized changes e.g. in the refractive index of a carriermaterial to emulate internal gratins therewith. Also specific coatingsof predetermined high or low refractive index have been applied on thesubstrate structures for controlling light propagation therein.Nevertheless, even these and other contemporary solutions have turnedout too restrictive, performance-wise inadequate, complex and expensivein the light of widespread industrial scale utilization.

SUMMARY

Thereby, the objective is to alleviate one or more problems describedhereinabove not yet satisfactorily addressed by the currentarrangements, and to provide a feasible alternative for producingvarious functional structures such as optically functional structuressuitable for use in the context of solar technology.

The objective is achieved by the embodiments of a laminate structure anda related method of manufacture in accordance with the presentinvention. It shall be noted that this summary is generally provided tointroduce a selection of concepts that are further described below inthe detailed description. However, this summary is not intended tospecifically identify the sole important or, in particular, essentialfeatures of the claimed subject matter and thus limit the claimedsubject matter's scope.

Accordingly, in one aspect of the present invention an integratedlaminate structure adapted for application in the context of solartechnology comprises

-   -   a first carrier element, such as a piece of plastic or glass,        preferably comprising optically substantially transparent        material enabling light transmission therethrough,    -   a second carrier element, such as a piece of plastic or glass,        provided with at least one surface relief pattern comprising a        number of surface relief forms and having at least one        predetermined optical function relative to light incident        thereon, said second carrier element preferably comprising        optically substantially transparent material enabling light        transmission therethrough,    -   the first and second carrier elements being laminated together        such that the at least one surface relief pattern has been        embedded within the established laminate structure and a number        of related, optically functional cavities have been formed at        the interface of said first and second carrier elements.

Preferably, the laminated elements are securely joined together bylamination so that no undesired gaps such as air gaps, naturallyexcluding the desired, preferably optically functional cavities createdby the at least one embedded surface relief pattern, remaintherebetween.

Further, one shall generally notice that when a surface relief patternor form of a carrier element is embedded during lamination, it does notappear on the surface of the constructed laminate structure and is not asurface relief pattern or form of the structure.

Yet, in optical applications the patterned laminate layers with the samerefractive index may form a single element in terms of optical functionrelative to light incident thereon.

In some embodiments, the first carrier element may be provided with atleast one surface relief pattern having a predetermined optical functionrelative to light incident thereon and comprising a number of surfacerelief forms. The pattern may be on the side facing the second carrierelement upon and after lamination (embedded), or on the opposite side,for example. In the latter case, the pattern may remain on the surfaceof the structure or be covered e.g. by a further element and be thusembedded. The patterns of the first and second carrier elements may forman aggregate multilayer pattern having at least one common function, forexample. A carrier element, such as the first or second carrier element,may generally be substantially planar, but also other shapes arepossible.

In some embodiments, the at least one surface relief pattern of thesecond carrier and/or of the first carrier element preferably embeddedwithin the laminate structure may indeed be configured to define anumber of preferably optically functional cavities therein optionallytogether with the facing portion of the first carrier and/or secondelement, respectively at the interface thereof. An embedded, closedcavity may be e.g. a micro-cavity or a nano-cavity as to the sizethereof. The cavities may contain a number of materials potentiallydifferent from the materials of the first and/or second carrierelements. A cavity may include or be filled with fluid such as air,suitable liquid, and/or solid. A cavity may include gel. Ink may also beapplied. Ink may be transparent or colored. The substances may have beenselected so as to provide a predetermined optical performance in termsof e.g. refractive index. The refractive index may differ from the oneof the associated carrier element, or it may be the same. A cavity mayhave a dot-like, an elongated or a more complex shape, for example.

In some embodiments, the at least one, optionally optical function of autilized, potentially embedded, surface relief pattern comprising anumber of surface relief forms may include a function selected from thegroup of: light directing function, light trapping function, reflectivefunction, transmissive function, transreflective function, couplingfunction, incoupling function, outcoupling function, polarizingfunction, diffractive function, refractive function, anti-glarefunction, anti-clear function, anti-reflection function, collimatingfunction, pre-collimation function, lens function, converging function,diverging function, wavelength modifying function, scattering function,coloring function, medium distribution function, and diffusing function.In the case of embedded patterns one or more functions may be achievedwith the established related cavities at the element interfaces. Theinterfaces or predetermined portion thereof may be made opticallytransparent with e.g. proper selection of refractive indexes (same), ifdesired.

A plurality of surface relief forms of the pattern may bear the samefunction. Alternatively, different forms of the pattern may beardifferent functionalities. In one embodiment, a single form may provideseveral, at least two, functionalities. The same pattern or even a formmay be configured to transmissively couple light and, on the other hand,reflect light, for instance. The functionality may depend on the nature,such as incident angle and/or wavelength, of light, and/or on the sideof the form the light is incident on, for example. A surface reliefform, either embedded or not, may be configured for a predeterminednumber of functions by properly selecting the associated material(contour material and fill material), dimensions, position and/oralignment, for instance.

In some embodiments, the laminate structure may include a third andoptionally a number of subsequent carrier elements. These may includefurther surface relief patterns thereon. The surface relief patterns maybe embedded within the laminate structure. Any of the first, second oroptional further elements may be a laminate or other type of multi-layerand/or multi-portion element. A middle element may be thicker than thesurrounding top and bottom elements such as films that may be providedwith a number of surface relief patterns to be optionally embedded, forinstance. Also the middle element may be provided with a surface reliefpattern that is embedded within the laminate during the manufacturing ofthe laminate structure.

In some embodiments, the integrated laminate structure may comprise aplurality of layers of (originally) surface relief patters. Eachlaminated element, such as a film, foil or sheet, may comprise one ormore surface relief patterns and construct one or more opticallyfunctional layers, respectively. Each layer may have a dedicated opticalfunctionality or several functionalities. A multi-layer pattern may beformed by a single carrier element initially having a layer of surfacerelief forms on both sides thereof, and/or a plurality of carrierelements, each provided with at least one layer of surface relief forms,may be utilized to collectively form the multi-layer pattern. The layersof the multi-layer pattern may have at least one collective function.

In some embodiments, the first and/or second carrier element issubstantially flexible and bendable. The degree of flexibility andbendability may differ embodiment-wise. For instance, a predeterminedbend, e.g. 180 degrees, may be achieved with a predetermined bend radiuswithout material breakage. Further carrier elements may be flexible andbendable as well. The laminate structure may be flexible and alsobendable.

The carrier element may be thin such as a thin film. The thickness of acarrier element may also vary depending on the embodiment. It may bejust a few nanometers up to several millimeters thick, for example. Theabove applies also to further carrier elements of the laminatestructure. However, clearly thicker element(s) may be alternativelyused.

In some embodiments, the first and/or second carrier element comprisesplastic material such as polymer or elastomer, glass and/or ceramicmaterial. Additionally or alternatively, other material(s) such assemiconductor materials, e.g. silicon or silicon wafer, may be used.

In some embodiments, a surface relief pattern to be optionally embeddedcomprises a number of surface relief forms defining at least one entityselected from the group consisting of: a grating, a grating groove, abinary shape, a slanted shape, a quadratic or rectangular shape, atriangular shape, a trapezoidal shape, a pixel, a grating pixel, aprotrusion, a recess, a hollow, and a lens shape.

In some embodiments, the laminate structure may comprise or form atleast part of a transmissive, reflective or transreflective element.

In some embodiments, the laminate structure contains or is provided witha functional surface layer such as a coating and/or a layer containingsurface relief forms. These forms may indeed remain on the surface ofthe laminate structure. The function, or “property”, thereof may includeanti-reflection function, hydrophobic function, hydrophilic function,and/or self-cleaning function, for example.

In some embodiments, a surface relief form and/or related pattern to beembedded in or be otherwise provided to the laminate structure maysubstantially be of submicron size regarding the length, depth/heightand/or width thereof. Alternatively, the size of the form and/or patternmay be few microns or several tens of microns, e.g. about 20 or about 30microns up to a number of millimeters. Even larger sizes may be applied.

In another aspect, a method for constructing an integrated structure foroptical applications in the context of solar technology comprises

-   -   obtaining a first carrier element, such as a piece of plastic or        glass, preferably comprising optically substantially transparent        material enabling light transmission therethrough,    -   obtaining a second carrier element, such as a piece of plastic        or glass, provided with at least one surface relief pattern        comprising a number of surface relief forms and having at least        one predetermined optical function relative to incident light,        said second carrier element preferably comprising optically        substantially transparent material enabling light transmission        therethrough,    -   laminating the first and second carrier elements together such        that the at least one surface relief pattern is embedded within        the established laminate structure.

Embedding the at least one surface relief pattern may practically causea number of related cavities to be located substantially at theassociated interface of the first and second carrier elements in thelaminate. Portion of the cavity edges may be thus defined by the facingsurface layer of the first carrier element.

In some embodiments, a roll-to-roll procedure is applied in the method.For instance, a roll-to-roll procedure such as roll-to-roll embossing orroll-to-roll imprinting may be applied for establishing the surfacerelief pattern on a carrier element. Alternatively or additionally, asurface relief pattern could be formed utilizing e.g. at least onetechnique selected from the group consisting of: embossing, imprinting,micromachining, UV embossing, UV imprinting, lithography, micro-molding,and casting. Yet, the lamination process may utilize roll-to-roll orplanar processing technology.

In some embodiments, a carrier element, such as the second carrierelement, is provided by at least one surface relief pattern such that apre-master element, e.g. a pre-master plate comprising a pre-masteringpattern, is first formed utilizing a suitable technique such aselectroforming, casting or molding, for example. A master element suchas a nickel shim, plastic master plate, cast material plate, or a moldedplate, may be formed based on the pre-master element. Optionally, thepattern(s) of the pre-master element may be modulated by a suitabletechnique such as printing. Drop filling by inkjet device may be appliedfor modulation, for instance, such that ink-filled portions of thepre-master do not appear as such in the target element, i.e. the masterelement.

The previously presented considerations concerning the variousembodiments of the laminate structure may be flexibly applied to theembodiments of the method mutatis mutandis and vice versa, as beingappreciated by a skilled person.

The utility of the present invention generally arises from a pluralityof issues depending on each particular embodiment. First of all, bothsimple and very complex high performance, integrated nano- ormicro-scale structures with various functionalities, such as opticalstructures, may be embedded within a laminate structure comprising atleast two elements defining at least two layers attached together. Theutilized lamination technique may be preferably selected so that theattachment is secure and/or there substantially remain no (unintended)gaps between the laminated elements. Further integrated elements, layersor coatings may be provided on any side of the obtained laminate. Inmost embodiments, the laminate structure may be manufactured with arelatively simple and low cost industrial scale method. Yet, theembedded structures of the laminate remain protected from externalimpulses and contamination. Service life of the related products isextended and many of them may be practically maintenance-free.

Also multilevel/layer embedded structures may be easily constructed.Internal light-trapping structures utilizing e.g. specific geometrics,refractive indexes and/or materials may be provided for internallyreflecting light. Light capture layers effectively capturing andcollimating light with a wide range of incident angles may beimplemented. The laminate may be applied, in addition to the context ofsolar energy, integrated electronics, semiconductors, (bio)medicalsystems, tribological systems, windows such as window lighting, greenhouse illumination, advertising, security applications, automotive andgenerally vehicle industry, street lighting, general lighting andvarious signs or plates such as traffic signs and luminous tags, forinstance.

Particularly in the context of solar energy and solar cells(photovoltaic cells), improvements in the operation efficiency due tomore efficient capturing of incident (surface) light to the solar cell,more efficient internal light trapping, and reduced if not completelyeliminated contamination problems, may be achieved. The solar cell mayremain static and implementing a moving means for adjusting thealignment thereof is unnecessary despite the increased efficiency. Thelaminate structure attached to the solar cell may be further providedwith additional functionalities and layers such as self-cleaningnanostructures, coatings etc. Larger functional surfaces may beconstructed. Rigid or flexible solar cell structures may be considered.

The expression “a number of” refers herein to any positive integerstarting from one (1), e.g. to one, two, or three.

The expression “a plurality of” refers herein to any positive integerstarting from two (2), e.g. to two, three, or four.

The expression “to comprise” is applied herein as an open limitationthat neither requires nor excludes the existence of also unrecitedfeatures.

The terms “a” and “an” do not denote a limitation of quantity, butdenote the presence of at least one of the referenced item.

Likewise, the terms “first” and “second” do not denote any order,quantity, or importance, but rather are used to distinguish one elementfrom another.

The term “light” refers to electromagnetic radiation such as visiblelight but being not limited to visible light.

The term “carrier element” may generally refer herein to an element ofthe laminate that comprises predetermined material, such as material forcarrying light, an element that comprises a predetermined functionalelement such as a coating or at least a portion of a structure such as asurface relief pattern or a related cavity, and/or an element thatsupports, carries, protects or is at least fixed to other one or moreelements in the finished laminate and therefore forms an integral partof the laminate.

Different embodiments of the present invention are disclosed in thedependent claims.

BRIEF DESCRIPTION OF THE RELATED DRAWINGS

Next the invention is described in more detail with reference to theappended drawings in which

FIG. 1a illustrates various problems associated with contemporary solarcell arrangements.

FIG. 1b illustrates various problems of surface relief structures whensubjected to typical use conditions, e.g. outdoors.

FIG. 2 is a cross-sectional illustration of an embodiment of thelaminate structure in accordance with the present invention.

FIG. 3 is a cross-sectional illustration of another embodiment of thelaminate structure in accordance with the present invention.

FIG. 4 is a cross-sectional illustration of a further embodiment of thelaminate structure in accordance with the present invention.

FIG. 5 is a cross-sectional illustration of a further embodiment of thelaminate structure in accordance with the present invention.

FIG. 6 is a cross-sectional illustration of a further embodiment of thelaminate structure in accordance with the present invention.

FIG. 7 is a cross-sectional illustration of a laminate structure for asolar cell in accordance with an embodiment of the present invention.

FIG. 8 is a cross-sectional illustration of a laminate structure forincoupling purposes in accordance with an embodiment the presentinvention.

FIG. 9a is a cross-sectional illustration of a structure for incouplingpurposes generally utilizing the principles set forth herein.

FIG. 9b is a cross-sectional illustration of two other structures forincoupling purposes generally utilizing the principles set forth herein.

FIG. 10 illustrates manufacturing an embodiment of the laminatestructure in accordance with a present invention.

FIG. 11 is a flow diagram disclosing an embodiment of the method ofmanufacture in accordance with the present invention.

FIG. 12 illustrates various aspects of potential roll-to-rollmanufacturing scenarios.

FIG. 13 illustrates selected elements of a manufacturing processresulting in a creation of an embodiment of the laminate structure inaccordance with the present invention.

DETAILED DESCRIPTION

FIGS. 1a and 1b were already contemplated in conjunction with thedescription of background art.

The principles of present invention may be applied in various usescenarios and contexts. The context may relate to the utilization ofvisible, infrared and/or UV light, for instance.

In some embodiments of the present invention, the laminate structure maybe produced from bulk elements such as bulk plates or films. These maybe provided with optical patterns having desired optical functions suchas coupling, e.g. incoupling or outcoupling, function. Patterns withsmall surface relief forms such as gratings, binary, blazed, slantedand/or trapezoidal forms may be utilized. Discrete patterns such asgrating pixels, small recesses, or continuous forms, elongated recessesor channels, basically almost any kind of two or three dimensionalforms, may be utilized. Preferably there are at least small flatportions, i.e. contact surfaces, on the laminate junction areas(interfaces) to enhance adhesion of the associate laminate layers and/orto obtain desired light propagation and/or other behavior.

The embedded surface relief pattern may form and be considered toinclude a number of closed cavities such as micro-cavities filled withair or other medium on the junction area. Also a number of largerstructures such as refractive structures may be established.Accordingly, the cavities are preferably optically functional and haveat least one predetermined optical function. Thus, when designing asurface relief form/pattern to be embedded, one shall naturallycontemplate the functionality of the form/pattern as embedded in thelaminate such that the surrounding laminate materials, shapes and forms,established cavities at the interfaces, etc. are properly taken intoaccount as to their e.g. optical effect.

In some embodiments, the outmost laminate element such as the top orbottom laminate element, when in use, may contain integral lightcoupling optics such as incoupling optics, outcoupling optics and/orpolarization gratings such as wire grid or other grating solutions. Theoptics may include embedded optics and/or surface optics.

In some embodiments, a number of light sources may be functionallyand/or physically connected to the laminate structure, via edge forexample, using suitable optionally laminate- and/or lightsource-integrated coupling optics such as collimation and/or reflectiveoptics. Bottom coupling is a further possibility.

In some embodiments, a multilayer such as dual-layer optic structure isimplemented by the laminate for coupling or other purposes. A layer orother element of the laminate may be configured for certain (range of)wavelength of light such as a certain range of wavelengths. Anotherlayer may be configured for other wavelengths. For instance, a surfacelayer or a layer closer to the surface may be configured for IR (longerwavelength) and another layer residing deeper in the structure forvisible light (shorter wavelength), or vice versa. The layer thicknessesmay be selected on target wavelength basis. With proper thicknesses,desired layers may be made practically invisible from the standpoint ofdesired wavelengths. The laminate may incorporate coupling optics, e.g.coupling layers with surface relief patterns, on multiple sides thereof.

In some embodiments, the laminate structure may be, instead of solartechnology or in addition to it, applied in advertising and indicativewindows, displays, signs or marks. An optically functional element, suchas a plate or film, which may be a laminate, may be disposed on top of atarget picture or other target element as a separate element orintegrated therewith (laminated, for instance). It may contain a surfacerelief pattern optionally located closer to the picture or the othertarget element than the opposite surface to enhance contrast. A binarygrating or other patterns may be utilized e.g. with a panel element.Binary grating may be desired for larger viewing angle applications anda blazed grating for narrower angle. Hybrid grating solutions arepossible as well. Diffusing optics may be utilized for hot spotavoidance and for more uniform illumination. The solution is alsoapplicable to UI solutions and license plates for instance. With licenseplates or other elements with identification data or other visual dataprovided thereon, the indicated numbers, letters, etc. may be laminatedinto contact with a front plate to make number/letter surroundingsilluminated, for example, for improved contrast.

In various embodiments of the present invention, one or more elements ofthe laminate structure may be substantially optically transparent,translucent or opaque. The required degree of transparency of eachelement naturally depends on each particular use case. For example, insome embodiments the preferred transmittance in relation topredetermined wavelengths of light (e.g. infrared, visible, or uv) mayreside within the range of about 80 to 95%, for instance, for a materialconsidered as substantially optically transparent in that context.

Reverting to the figures, FIG. 2 depicts one scenario wherein anembodiment of the present invention may be applied. The integratedlaminate structure 202 comprises two planar carrier elements 204 and 206laminated together. More elements could be added, if needed. The brokenline denotes the (ex-)interface between the two laminated elements 204(hereinafter “top element” due to the location in the figure, whereas inuse the position could be “top” or “side”, for example, depending on thealignment of the laminate), 206 (hereinafter “bottom element” for thecorresponding reason) in the figure. The interface may be opticallytransparent as described hereinbefore. Few light rays are visualized assolid line arrows in the figure.

The top element 204 has been originally provided with a surface reliefpattern comprising a number of protruding surface relief forms 208 onthe bottom thereof with corresponding recesses 210 in between. The topelement 204 and bottom element 206, which may be considered as asubstrate carrier of the top element 204 and a partial substrate for thecreated cavities defining at least a portion of the walls thereof at theinterface of the elements 204, 206, have been then laminated together sothat the protrusions 208 of the surface relief pattern extendingdownwards with the shape of e.g. a truncated cone (note thecross-sectional form of an isosceles trapezoid in the figure) havecontacted the alignment-wise corresponding surface portions of thebottom element 206 having a substantially flat contact surface in theillustrated case. Thereupon, the recesses 210 have formed preferablyclosed cavities potentially including material such as air trappedtherein unless a vacuum has been provided. The material may thus have arefractive index different from the surrounding material. If thematerial of the element 204 is plastic, its refractive index isgenerally higher than the refractive index of air, for instance.

Regarding the use of different materials or refractive indexes ingeneral, when multiple elements such as material layers bear the sameindex, these may be regarded as a single element by light, thus definingan optically transparent interface. On the contrary, different materialswith unequal indexes may be utilized in order to modify lightmanagement, e.g. total internal reflectivity, as desired.

The utilized shapes and/or refractive indexes nair, n1, n2 of thematerials carried by the elements 204, 206 may have been selected so asto provide a desired functional effect in terms of light propagation. Itis illustrated in the figure by the arrows how a number of light rayswith different incident angles may be collimated by the appliedconfiguration of laminate layers and surface relief pattern therein toadvance towards the bottom of the laminate in substantiallyperpendicular fashion. Thus the top element 204 may be considered to actas a light capture layer for the underlying one or more elements 206. Insome embodiments, the element 204 may be thin, essentially a film, withonly e.g. few nanometers thickness, whereas in some other embodiments itmay be several millimeters thick or even considerably thicker. The sameconsiderations apply to the bottom layer 206. The shown or a similarembodiment could be applied in the context of window illumination orsolar cells, for instance.

FIG. 3 discloses another embodiment 302 with two carrier elements 304,306. In this embodiment, the bottom element 306 contains a surfacerelief pattern 308 with protrusion 308 a and intermediate recess 308 bforms, or “profiles”, on top of which a flat top element 304 islaminated. Again, the established cavities may contain air and/or someother material(s).

FIG. 4 discloses an embodiment 402 in which a plurality of differentembedded surface relief forms is configured to form a number of embeddedsurface relief patterns relative to elements 404, 406 laminatedtogether. Triangular 408, trapezoidal 410 and slanted (rectangle orsquare) 412 forms are shown in the figure. For example, the forms andrelated patterns may have been configured for outcoupling and/or othertype of light redirecting as visualized in the figure by the arrows.Forms of different shape and/or material may be configured so as toprovide a common, collective optical function, or they may be utilizedfor different purposes. A certain embedded surface relief form may havemultiple uses depending on e.g. the incident angle and/or face of light.For example, in the figure the leftmost triangle form or cavity has bothoutcoupling and light trapping functionalities, which has beenvisualized by the two rays. The established cavities may contain airand/or some other material(s). The laminate structure 402 may in someuse scenarios be disposed on top of and optionally laminated with anindicative element such as a poster, sign or plate, for example.

FIG. 5 illustrates a further embodiment 502 wherein three carrierelements 504, 505, 506 have been laminated together. Each of theelements 504, 505, 506 may contain a number of surface relief patternsand/or other features, but in the illustrated extract the bottom element506 is free from them and merely acts as substrate for the upperelements 504, 505. The bottom element 506 may, in some use cases,contain and/or exhibit e.g. indicative data (advertisement data,informative data). It may be a sign or plate with indicative dataprinted or otherwise constructed thereon, for instance.

The middle element 505 comprises a surface relief pattern ofsubstantially rectangular (binary) forms 508, which may (being notvisible in the cross-sectional figure) be dot or pixel like forms orlonger grooves such as grating grooves or corresponding protrusions. Thetop element 504 comprises a pattern of triangular forms 510. The topelement 504 may form in the laminate at least one optically functionallayer the embedded surface relief pattern of which has at least onepredetermined function such as incoupling or outcoupling function. Themiddle element 505 may form at least one other optically functionallayer the embedded surface relief pattern of which has potentially otherpredetermined function such as reflective function. Again, a number ofdifferent forms and/or layers of microstructures may be configuredregarding a common functionality from the standpoint of a desiredfunctionality such as predetermined light incoupling or outcouplingproperty such as collimation or decollimation property. The cavitiesestablished by embedded surface relief forms may contain air and/or someother material(s).

FIG. 6 discloses a further embodiment 602 wherein the top element 604 ofthe laminate comprises at least one pattern comprising a number offirst, essentially square-shaped, surface relief forms 608 and second,essentially rectangular, surface relief forms 610 on the surface facingthe bottom element 606 in the laminate structure. The forms may havesimilar or different purposes. For example, the first forms 608 may beconfigured in terms of the utilized material(s), dimensions and/orpositioning, for functions such as outcoupling or incoupling whereas thesecond forms 610 are for reflection, potentially specular reflection.

FIG. 7 illustrates a further embodiment especially suitable for thecontext of solar energy production, i.e. solar power, and solar cells. Acarrier element such as a thin film element 702 (the depictedthicknesses and other dimensions are generally not in scale for claritypurposes) potentially configured to act as a light capture element maybe provided with a surface relief pattern comprising a plurality ofsurface relief forms 708 capable of collimating light (with a narrowerdistribution) in the laminate structure towards predetermined direction,substantially the direction of the underlying components of the solarcell 706 from a wider range of incident angles of external light,typically sunlight, penetrated through the surface of the element 702and incident on the pattern. The height/depth of the surface reliefforms 708 of the pattern may be about 10 μm, for instance.

The film element 702 and a carrier element 704 that may also act as thecover plastic or glass of the solar cell structure (indeed, often thesolar cells are provided with integral cover glass) may be firstlaminated together and stored and delivered for later joining with therest 706 of the complete solar cell structure as suggested herein, forexample. This is highlighted at 702 a of the figure wherein the verticalarrow depicts the fact how the already laminated film element 702 andcover glass 704 are to be joined with the solar cell stack 706 typicallycomprising a plurality of different layers and related elementsillustrated in the figure by a plurality of horizontal lines.

For example, the solar cell structure 706 potentially stacked below thecover glass 704, which preferably contains tempered glass, mayincorporate one or more layers or elements selected from the groupconsisting of: a back contact, a p type semiconductor, an n typesemiconductor, a front contact, transparent adhesive, andanti-reflective coating.

At 702 b, a use situation after completing the manufacturing of theoverall solar cell structure comprising also the film element 702 forlight capturing as an integral part is shown. Alternatively, the filmelement 702 may be provided as such onto the solar cell structure havingthe cover glass 704 already in place. As a further alternative orsupplementary option, the element 702 may be provided between the glass704 and the rest of the solar cell structure 706. Still as a furtherexample, the glass 704 may be provided with a surface relief pattern.The established cavities 709 may contain air and/or some othermaterial(s) left or specifically disposed therein during themanufacturing process of the laminate structure.

Generally, the described nano- and microcavity film techniques can beutilized in different layers of a solar cell product 702 b. E.g. complexundercut profiles are possible. Also multi-layers with multi-profilesare suitable as contemplated hereinbefore. An optically functional layercan be produced/applied on the top surface, some internal surface (e.g.to the middle under the glass plate) or directly on the siliconsurface/solar cell surface including possible nanoprofile in thesilicon/photovoltaic surface to improve light absorption. The opticalprofiles are preferably fully integrated.

The arrows depict in the figure how the suggested construction mayenhance the efficiency of the solar cell in a variety of ways. Inaddition to or instead of incident light coupling and/or directing (e.g.collimation) function 708 a, reflective and generally “light-trapping”functions 710, 712 may be achieved by the utilized patterns includingcavities, their positioning, alignment and material selections. Thelight traps may be thus formed without true, reflective mirror surfacesin the carrier material.

The solar cell structure suggested herein may provide about 20-40%higher efficiency than the conventional solutions, whereupon the overallefficiency may approach e.g. 40% or 50%. Both rigid and flexible solarcell materials and structures may be applied and constructed.

FIG. 8 visualizes an embodiment 801 wherein the light capture film orplate element 802 laminated on the glass 804 protecting the rest 806 ofthe solar cell has been further provided with a functional surface layer808 implemented by a specific film, a coating, a surface relief pattern,or any combination of the above and/or other elements, for instance.

For example, a number of anti-reflective (AR) and/or self-cleaning(nano)profiles may be utilized to minimize surface reflection andcontamination. The AR functionality may preferably enable incouplingsunlight even with very large incident angles relative to the structuresurface (normal), such as angles of about 70 or 80 degrees, into thestructure from the atmosphere so that the solar cell receives as muchlight as possible and the efficiency thereof may be maximized. This isindicated in the figure by the arrows 808 b. The embedded surface reliefpattern 802 a of element 802 may be then utilized to direct andcollimate the incoupled light towards the solar cell 806. The pattern802 a may also be designed so as to be capable of coupling aconsiderable range of incident angles, e.g. a total range of 120, 130,140, 150 or 160 degrees, as desired.

For example, the pattern 802 a may be configured to couple incidentlight such as sunlight having entered the structure so that the incidentangles properly coupled optionally define a range of at least about 120,130, 140, 150 or 160 degrees, and wherein the pattern is configured tocouple the incident light with a collimation function substantiallytowards a predetermined direction of a solar cell.

Also integrated reflectors with micro-cavities may be adopted for solarcell structures, which may improve maintaining the sunlight longerinside the structure, whereupon energy absorption can be potentiallyimproved even more. Accordingly, the suggested laminate structure may insome embodiments improve the efficiency of the solar cell considerably.

It shall be mentioned that in some embodiments the constructed overallsolar cell structure including the light capturing or other laminatedelement may contain multiple, e.g. two, functional, such asanti-reflective, layers. One may be disposed on either side of the coverglass and the other on the other side in connection with the lightcapture film element such that it preferably receives the external,incident light prior to the light capture film element.

The principal ideas presented hereinbefore relative to a solar cellcoupling film or other element with a large incidence angle collimationare generally applicable to other scenarios as well including e.g.greenhouse related embodiments. These kinds of films may increase theuse of sun light without extra mirrors, for instance. The transparencyof the film may be enhanced by means of minimized pattern featuresrelative e.g. to the size thereof.

In some embodiments, a number of embedded reflectors such asnanoreflectors may be manufactured by the techniques presented herein.Small patterns, e.g. grating based reflecting profiles can be laminateddirectly on e.g. a planar reflector and those small surface reliefpatterns of laminated elements can be completely embedded, unlike e.g.with conventional retroreflector films.

In some embodiments, a polarizer may be manufactured in accordance withthe principles set forth herein. E.g. a grating/wire grid polarizer maybe produced optionally by a roll-to-roll method. Basic profiles may bemanufactured by applying UV curing and related curable material, forexample, after which deposition coating by higher refractive index bymeans of laser assisted deposition may be executed on the line. Thelaser may be used to deposit many different materials. Also orientateddirectional deposition (on-side deposition, asymmetric deposition) ispossible. A grating profile may be binary, slanted, quadrate, etc. withdifferent slanted surfaces, etc.

In some scenarios, a number of features of the present invention may beutilized in connection with light incoupling and related solutions.Nowadays, e.g. LED light incoupling and collimation for a typicallyplanar element may be a critical issue. A flat ball lens bar optionallyin a row form is a unique solution. It could contain 2D or 3D surfacedepending on the collimation axis. Principally, one axis collimation maybe enough. Such an optical solution may be produced separately ortogether with the planar element. Possible manufacturing methods includeinjection molding, casting, laser cutting, etc. It is possible to usemirror surface on the top and bottom for the light direction control.Also special grating orientating patterns on the edge and/or e.g. topmay provide desired solutions. A wedge type of collimation with airmedium is a further feasible option.

FIG. 9a illustrates a scenario for incoupling purposes. The incouplingelement 902 includes a number of potentially embedded (e.g. a laminatedfilm) reflector forms 908 and a potentially embedded (e.g. laminatedfilm) light directing structure 906 that may be provided as a laminatedlayer/element on a predetermined surface of the carrier material 904such as plastic or glass. In the illustrated case, a plurality of LEDs910 is applied as light sources.

FIG. 9b illustrates further scenarios relating to the incouplingstructures. At 920, on the left 920 a, top/bottom view of one embodimentis shown with a plurality of light sources such as LEDs 910, incouplingforms such as lens forms 924 a and a target element 922. The shown lensforms are basically circular or ellipsoidal. On the right at 920 b,other embodiment with different incoupling forms such as lens forms 924b is presented.

At 930, potential, corresponding side views are shown with additional,preferably integrated, reflector elements 932. Lens shapes 924 a, 924 bare apparent in the figure.

Thus in various embodiments of the present invention, a laminated lenselement such as lens film may be utilized to form nano-/microcavitycoupling structures. Embossed/imprinted films can be laminated on acarrier material/film. This makes possible to produce new lensstructures with multi layer patterns. Another benefit is that opticalpatterns are completely integrated/embedded and those can't be defectedor destroyed easily. There are several feasible applications such asstreet lamps, halogen replacements, etc.

Another potential illumination lens is a non-direct transmissionelement, which couples light e.g. from the air medium and directs it topreferred angles. One surface may have a reflector (2D or 3D) and theother a surface coupling pattern (2D or 3D).

A light source, such as LED, bar may be collimated at least in 2Dhorizontal direction. This may make coupling pattern more simple andefficient. The solution may have applications in e.g. street lights,public illumination, etc.

Another application is a light bar, rod or tube, in which the couplingstructure or film forms or is in the outer or inner surface thereof forcoupling and directing the light. In the tube solution a reflector rodmay be utilized in the center (inner part). A coupling film may also belaminated in the glass to direct the light to preferred angles (insideor outside).

One additional benefit with surface relief based, optionally embedded,lenses such as grating lenses is efficiency, which is better than withconventional Fresnel lens, for example, due to e.g. smaller featureshaving much less back reflection than conventional larger patterns, andalso to the possible (bottom) location of the patterns. When thosepatterns are on the bottom side of the overall structure, there is notso much direct back reflection, because medium carrier is on the topside.

This may be a benefit for e.g. traffic signs due to the lower sunphantom effect (back reflection). Additionally, the solution is suitablefor e.g. brake and signal lights in vehicles.

FIG. 10 illustrates a laminate structure 1002 comprising a plurality ofelements 1004, 1006 in accordance with an embodiment of the presentinvention. A number of embedded, integrated functionalities may beprovided to the laminate 1002 by adding new elements such as functionalcarrier films 1004 with surface relief patterns and/or particularmaterial (e.g. in terms of refractive index) thereto. Surface reliefpatterns may be established directly on the target surfaces. Curablematerials such as lacquer may be utilized. Basically the necessarycoupling and/or other optics may be laminated as a film or a thickerelement to the carrier entity thereof. Roll-to-roll processingtechniques are possible and often preferred naturally still depending onthe embodiment and the nature such as flexibility and thickness of theapplied elements.

FIG. 11 discloses, by way of example only, a flow diagram of a method ofmanufacture in accordance with the present invention.

At start-up 1102 the necessary equipment such as embossing/imprintinggear, molding gear, casting gear, lamination gear, curing gear and/orroll-to-roll gear is obtained and configured. Yet, source materials forlaminate layers and the lamination itself, such as necessary adhesives,if any, are obtained.

At 1104, a first carrier element defining at least one layer of theintegrated laminate structure is obtained. The first element may beprovided with desired surface relief patterns and coatings. Curablematerial such as lacquer may be provided, embossed or otherwiseprocessed to contain a surface relief pattern and cured, for example.The element may be molded or cut to desired dimensions from a largerpiece of source material such as plastic or glass. It may be subjectedto a number of treatments and/or provided with adhesive for laminationpurposes. Optionally, the first element is a multilayer element such asa laminate element itself. It may be contain e.g. a plurality of solarcell constituting layers and/or elements.

At 1106, a second carrier element to be utilized in the integratedlaminate structure is obtained. It contains a number of surface reliefpatterns that may be fabricated, as the ones of the first element, withdifferent methods, such as roll-to-roll embossing/imprinting,lithography, micro-molding, casting etc. on the surface thereof. It maycontain plastic, glass or ceramic material, for example. Suitable curingmay be applied. Further, desired additional elements and/or coatings maybe provided to the second element. The second element may be amultilayer element such as a laminate element.

In conjunction with the present invention, a surface relief pattern maybe produced by means of pre-master pattern, master pattern and relatedelements. A pre-master element with a pre-mastering pattern may be firstcreated by micro machining, lithography, imprinting, embossing and/or bysome other method. This pre-mastering pattern may be then replicated byelectroforming, casting or molding. Then formed nickel shim, a plasticmaster plate, a cast material plate, a molded plate may containplurality of micro relief pattern on the surface, preferably smallgrooves, recesses, dots, pixels, etc.

The preferably negative relief patterns of the pre-master areadvantageously suitable for the inkjet and/or printing modulationprocess. This modulation process may be based on a profile fillingmethod, in which the existing groove, recess, dot, pixel, etc. ispotentially completely filled with inkjet/printed material. Thismaterial is dispensed by forming small pico-drops in order to fill and“hide” the existing patterns. Method is suitable to complete a fillingfactor modulation on the surface of the target element, i.e. the master.Naturally the method is suitable for many other applications as well,and not only to filling factors. It's suitable also to design differentdiscrete figures, icons, forms and shapes, for example. This makes itpossible to create low cost optical designing process, which is fast,flexible and first of all, easy to utilize. A skilled person willrealize that the profile filling method suggested herein is generallyfeasible also in other contexts than merely the laminate context of thepresent application.

The fill material such as ink could be transparent and optically clear,which has preferable the same refractive index than the plate material.This way it is possible to make real functional tests and trials. Bute.g. colored ink is also possible, but then replication process may beneeded in order to obtain a functional, optical test part.

One issue to consider may be the drop size and material viscosity. Thismight be important in terms of controlled and high quality filling. Ifthe viscosity is too low, the drop will flow for large area and it goesalong the groove bottom. Thus completely filled structure is gettingmore difficult to achieve. If the viscosity is high, the drop size isgetting bigger, but the form is more compact and doesn't flow on thegroove too much. A preferred solution may therefore include low viscousmaterial, which guarantees small drop size. And if utilizing only asmall pattern, discrete grooves, recesses, dots or pixels, the dropadvantageously fills only preferred patterns in the desired location.Thus the pre-master may be preferably patterned with small pixels ordiscrete profiles.

At 1108, the first and second elements, and optionally further elements,are laminated together utilizing suitable pressure, heat and optionallyadhesive(s) between the elements to be laminated together. Feasiblecuring may be applied. The embedded surface relief profiles basicallyestablish associated micro- and/or nanocavity patterns. Potentially verycomplicated volumes (e.g. cavities) may be created, which is difficultif not impossible by other methods. Multilevel/multilayer patterns arepossible by laminating several patterned medium carriers (elements)together. An element to be included in the laminate may comprise asurface relief pattern on multiple sides thereof. Different patterns canprovide different functionalities in the laminate.

One realization implies laminating e.g. UV embossed/imprinted thin films(patterned films) on a thicker carrier such as plastic or glass plateand then executing the final curing in order to obtain good adhesionbetween laminated film and plate. Roll-to-roll lamination is possibleprovided that the laminated elements are suitable, i.e. thin/flexibleenough, for the purpose.

At 1110 further elements and/or functionalities may be provided to thelaminate. Post-processing actions such as cutting, excess materialremoval, (re-)reeling, testing, etc. may be performed.

The method execution is ended at 1112.

The mutual ordering and overall presence of the method items of themethod diagrams disclosed above may be altered by a skilled person basedon the requirements set by each particular use scenario. Execution ofsome method items may be alternately repeated during the method asillustrated by the broken arrows.

FIG. 12 illustrates various aspects of possible roll-to-rollmanufacturing scenarios applicable in connection with the presentinvention. In the shown sketch, two elements, basically films, sheets orfoils, 1204, 1206, are laminated together and a surface relief pattern1206 b is replicated by the cylinder/roll 1208 to the element 1206during the process prior to the lamination. The laminate structure 1216is formed and the pattern 1206 b is laminated within the structure 1216by the lamination cylinder/roll 1210. Pre-curing 1212 such as UV lightcuring may take place as well as post-curing 1214, optionally again UVcuring. A number of further process actions such as cutting, reeling andtesting actions may be implemented (not shown in the figure). A targetelement such as element 1204 could also be provided with multipleadditional layers such as films optionally on both sides thereof. Thismight be implemented in one go, if the amount and nature of necessaryhardware such as cylinders/rolls etc. is sufficient. Alternatively, thesame result could be obtained via multiple runs during which e.g. asingle layer is added to the laminate per round.

FIG. 13 illustrates different potential items of a further embodiment ofa preferably roll-to-roll based manufacturing method in accordance withthe present invention. The particular example is about foil lamination,but a skilled person will realize the principles apply to various othercarrier elements to be laminated as well. At 1302, it is generally shownhow a functional such as an optically functional element may be providedto a carrier material such as a film. As alluded in the figure, a foil,film or other type of element may be first provided 1312 with materialsuch as lacquer that enables forming surface relief forms therein and iscurable. The material hosting the surface relief pattern may indeed bethermally curable, UV curable, moisture curable, or e-beam curable, forinstance, among other options. Additionally, combined curing techniquesutilizing at least two curing methods such as UV curing+thermal curing,UV curing+moisture curing, thermal curing+e-beam curing, etc. may beapplicable depending on the used materials.

After establishing 1316 a surface relief pattern “A” on thelacquer-provided foil by embossing or some other technique, the patternmay be, when needed, pre-cured 1318 by a suitable method such as UVcuring potentially followed by lamination 1320 relative to a carrierelement such as another film. The established laminate “A” including thepattern A preferably as embedded may be cured at 1322 after which it afurther functional element such as foil may be coupled, preferably bylamination 1324, thereto, which is generally shown, by way of exampleonly, at 1304 with substantially similar process items indicated byidentical reference numerals supplemented by ‘b’, however. Nevertheless,these process items do not have to be similar and e.g. different patternformation technique and/or curing technology could be applied. Thefurther functional element may include a pattern “B” as indicated in thefigure. The final laminate comprising both patterns A and B may besubjected to a number of applicable curing 1326 procedures and/or othertreatments.

Consequently, a skilled person may, on the basis of this disclosure andgeneral knowledge, apply the provided teachings in order to implementthe scope of the present invention as defined by the appended claims ineach particular use case with necessary modifications, deletions, andadditions, if any.

For example, in some embodiments, one or more elements of the integratedlaminate structure may contain the explained cavity optics forpredetermined purpose such as uniform illumination or discreteillumination. The optically functional elements may be integrated bylamination with other elements such as covers of various electronic orother devices.

The present invention enables providing localized optical functionswithin integrated structures such as laminates. Local effects and visualindications, such as informative indications, may be created in certainembodiments thereof.

Generally in different embodiments of the present invention the reliefforms may be positive or negative relative to the associated surfacelevel of the carrier substrate.

In some embodiments, instead of or in addition to lamination, theelements of the integrated structure may be attached using some othermethods such as mechanical fastening structures, mere adhesives, etc.

In some embodiments, a laminate structure according to the presentinvention may be further integrated with or configured to contain otherelements such as chips, chip packages, solar cell structures, lightsources, lighting elements, electronics, cover or body structures, etc.

Each of the afore-explained various functions/functionalities may beimplemented in the laminate structure by a dedicated element, a sharedelement or by a plurality of cooperating elements.

Instead of or in addition to optics and particularly solar technology,the laminate solution presented herein could be utilized in othercontexts such as microfluidics. E.g. cooling structures and coolingchannels could be manufactured therewith. Also lubricant channels couldbe formed.

1. An integrated laminate structure for a solar cell, comprising a firstcarrier element, configured as entirely flat, planar element, andoptionally comprising optically substantially transparent materialenabling light transmission therethrough, a second carrier element,configured as a flat, planar element with an at least one surface reliefpattern formed thereon, said pattern comprises a number of prominentsurface relief forms configured to establish flat junction areas withthe first carrier element and thereby having flat contact surfaces,wherein said first and said second carrier elements are composed of anoptionally substantially transparent material enabling lighttransmission therethrough, the first and second carrier elements beinglaminated together such that an at least one embedded relief pattern hasbeen formed within the established laminate structure, thereby eachsurface relief form of the second carrier element has established a flatjunction area with the first carrier element and a number of related,optically functional cavities have been formed at the interface betweensaid first and second carrier elements.
 2. The integrated laminatestructure of claim 1, wherein the cavities comprise fluid or soliddifferent from the material of the second and optionally first carrierelement, optionally with different refractive index relative to eitheror both the carrier elements.
 3. The integrated laminate structure ofclaim 1, wherein the cavities comprise substantially air or othergaseous medium, optionally with a refractive index different from theone of surrounding material.
 4. The integrated laminate structure ofclaim 1, wherein the cavities comprise liquid or gel, optionally with arefractive index different from the one of surrounding material.
 5. Theintegrated laminate structure of claim 1, wherein said second carrierelement is substantially a film, optionally substantially thinner thansaid first carrier element, and optionally being a bendable film.
 6. Theintegrated laminate structure of claim 1, further comprising afunctional, optionally optically functional, film.
 7. The integratedlaminate structure of claim 1, wherein the embedded relief pattern isconfigured to couple incident light, optionally sunlight, with acollimation function in a predetermined direction of the underlyingsolar cell, said embedded relief pattern further configured to couplelight incident thereto within a total range of at least 130 degrees. 8.The integrated laminate structure of claim 1, comprising at least oneelement selected from the group consisting of: an embedded reliefpattern or a relief form configured for internal light trapping byback-coupling and/or redirecting light substantially back to thedirection it arrived at the pattern or form from, and an embeddedsurface relief pattern or form configured for internal light couplingand/or redirecting without reflective function.
 9. The integratedlaminate structure of claim 1, comprising at least partially embeddedmultilayer pattern of surface relief forms with a common function or atleast jointly designed multiple functions, wherein the multilayerpattern may be established by one or more elements laminated together inthe laminate structure.
 10. The integrated laminate structure of claim1, wherein the embedded relief pattern comprises an at least one opticalfunction selected from the group consisting of: light directingfunction, light trapping function, reflective function, transmissivefunction, transreflective function, coupling function, incouplingfunction, outcoupling function, polarizing function, diffractivefunction, refractive function, anti-glare function, anti-clear function,anti-reflection function, collimating function, pre-collimationfunction, lens function, converging function, diverging function,wavelength modifying function, scattering function, coloring function,medium distribution function, and diffusing function.
 11. The integratedlaminate structure of any claim 1, wherein the first carrier element,the second carrier element, or a further carrier element comprises atleast one material selected from the group consisting of: plastic,elastomer, polymer, glass, semiconductor, silicon, adhesive, resin, andceramic material.
 12. The integrated laminate structure of claim 1,further comprising a functional layer in the form of a coating and/or asurface structure, optionally as a surface relief pattern.
 13. Theintegrated laminate structure of claim 12, wherein the functional layercomprises at least one additional function selected from the groupconsisting of: anti-reflection function, hydrophobic function,hydrophilic function, and self-cleaning function.
 14. The integratedlaminate structure of claim 1, comprising a number of forms in theembedded relief pattern of sub-micron size.
 15. The integrated laminatestructure of claim 1, wherein the surface relief pattern comprises atleast one form selected from the group consisting of: a groove, aprotrusion, a ridge, a recess, a binary form, a slanted form, arectangular form, a quadratic form, a triangular form, a grating pixelform, a trapezoidal form, an isosceles trapezoidal form, and a lensform.
 16. A solar cell structure comprising the integrated laminatestructure of claim 1, optionally as an integrated, fixed part thereof.17. The solar cell structure of claim 16, wherein the first carrierelement or the second carrier element of the integrated laminatestructure comprises a semiconductor material provided with a surfacerelief pattern increasing the surface area thereof.
 18. The solar cellstructure of claim 17, wherein the surface relief pattern is configuredto enhance light absorption into the material of the solar cell and/orto reduce reflections therefrom in order to raise the efficiency of thesolar cell.
 19. The integrated laminate structure of claim 1, comprisinga number of carrier elements, wherein at least two of said carrierelements incorporate an at least one relief pattern, said at least twopatterned carrier elements being laminated together such that at leastone surface relief pattern of any one of said patterned carrier elementshas been embedded within the integrated laminate structure.
 20. A systemcomprising a solar cell structure and an integrated laminate structureaccording to claim 1, wherein the integrated laminate structure isdisposed on and optionally secured to the solar cell structure.
 21. Amethod for constructing an integrated structure for a solar cell,comprising obtaining a first carrier element, configured as an entirelyflat, planar element, obtaining a second carrier element, configured asa flat, planar element with an at least one surface relief patternformed thereon, said pattern comprises a number of prominent surfacerelief forms configured to establish flat junction areas with the firstcarrier element and thereby having flat contact surfaces, wherein saidfirst and said second carrier elements are composed of an opticallysubstantially transparent material enabling light transmissiontherethrough, laminating, optionally in a roll-to-roll fashion, thefirst and second carrier elements together such that an at least oneembedded relief pattern is formed within the established laminatestructure, thereby each surface relief form of the second carrierelement established a flat junction area with the first carrier element,and a number of related, optically functional cavities are formed at theinterface of said first and second carrier elements.
 22. The method ofclaim 21, wherein during manufacturing a master for surface reliefproduction, a pre-master with a pattern of surface relief forms isestablished and the pattern is modulated to generate the master byinclusion of an optionally removable material in the pattern to fill anumber of forms thereof and to therefore prevent their introduction tothe master.
 23. The method of claim 21 wherein the surface relief formis produced using at least one technique selected from the groupconsisting of: embossing, imprinting, lithography, molding,micro-molding, and casting.
 24. The method of claim 21, wherein adhesiveand/or curing is applied during the lamination and/or forming of thesurface relief pattern.
 25. The method of claim 21, wherein the secondcarrier element comprises or is provided with curable material,optionally a curable lacquer, that is adapted to host the at least onesurface relief pattern.